Machine for semicontinuous coating of mateiral in strip form



June 19, 1951 J. WISHART ETAL 2,557,584

MACHINE FOR SEMICONTINOUS COATING 0F MATERIAL IN STRIP FORM Filed Jan. 21, 1948 4 Sheets-Sheet 1 GEORGE H. BANC'ROFT AND JAMES W[5'HAR INVENTORS AL-*4 MM June 19, 1951 J. WISHART ETAL 2,557,534

MACHINE FOR SEMICONTINOUS COATING 0F MATERIAL IN STRIP FORM Filed Jan. 21, 1948 4 Sheets-Sheet 2 GEORGZ'H BANCROFT AND JAMES WISH/ RT INVENTORS fl w JW W W @ALMM ATTORNEY? June 1951 J WISHART ETAL 2,557,584

MACHINE FbR SEMICONTINOUS COATING 0F MATERIAL IN STRIP FORM Filed Jan. 21, 1948 4 Sheets-Sheet 3 BYM JZ M W 4 wax/ r04 June 1951 J. WISHART ETAL 2,557,584

MACHINE FOR SEMICONTINOUS COATING 0F MATERIAL IN STRIP FORM Filed Jan. ,21, 1948 4 Sheets-Sheet 4 COAT/N6 DEG'ASSl/VG CHAMBER w CHAMBER 57 DIFFUSS/ON 0R cows/v51: r/o/v PUMPS 54 LARGE MECHANICAL LARGE MEOHAN/GdL BACK/N6 PUMP BACK/N6 PUMP GEORGE H BAA/CIPOFT AND (JAMES W/JHART' INVENTOR. 44, fa

ATTORNEKS Patented June 19, 1951 MACHINE FOR SEMICONTINUOUS COATING F MATERIAL IN STRIP FORM James Wishart and George Hubert Bancroft,

Rochester, N. Y., assignors, by mesne assignments, to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application January 21, 1948, Serial No. 3,474

4 Claims. 1

This invention relates to an improved apparatus for coating materials under vacuum.

It is an object of this invention to provide an apparatus which will effectively and economically coat a roll of strip material under vacuum. Another object is to provide a combination vacuum coating and degassing apparatus with an interconnecting evacuatingsystem arranged for maximum use and efficiency. A further object of this invention is to provide a semi-continuous vacuum coating apparatus of large productive capacity. A still further object is to provide a combination degassing and coating apparatus. Another object is to improve the state of the art. Other objects will appear hereinafter.

These and other objects are accomplished by this invention which, as exemplified by a preferred embodiment, includes a gas-tight coating chamber, means for vaporizing coating material within said chamber, controllable means for rolling and unrolling strip material to be coated within said chamber in proximity to said vaporizing means, means for evacuating said coating chamber to a pressure below about microns Hg, a separate gas-tight degassing chamber for degassing material to be coated, controllable means for rolling and umolling material to be degassed within said chamber, an ejector pump suitable for operation in about the range 1 mm. Hg -10 microns Hg connected to said coating chamber and said degassing chamber. shut-oil valve means between said ejector pump and each chamber, a small mechanical backing pump connected to said ejector pump, valve means for isolating said ejector pump and said small mechanical backing pump from the rest of the apparatus, a mechanical backing pump of substantial capacity with gas-tight connections to said ejector pump, said degassing chamber and said coating chamber, and shutoff valve means in each of said connections for limiting the operation of said mechanical backing pump of substantial capacity to a particular portion of the apparatus. The ejector type oil condensation pump has proved to be very satisfactory but other types' of oil condensation pump may be used.

In the accompanying drawings, wherein like numerals refer to like parts, Fig. 1 is a view of the apparatus looking at the coating chamber with the coating chamber walls partially cut away to show the rolls of sheeting material.

Fig. 2 is a View of the apparatus showing both the coating chamber and degassing chamber and with the coating chamber walls partially cut away to reveal the vaporizing element.

Fig. 3 is an enlarged view of the vaporizing unit.

Fig. 4 is a view of the degassing chamber showing the manner in which rolls of material are exposed to the high degassing vacuum.

Fig. 5 is another view of the degassing chamber. l HIRE Fig. 6 is a schematic drawing showing the arrangement whereby evacuating pumps are connected to the coating and degassing chambers and shut-off valves placed in the lines to obtain maximum use and efficiency of the entire unit.

Referring to Figs. 1 to 6, numeral l0 designates the baseplate of the coating chamber which rests on supporting table l8. Bell jar makes gas-tight contact with baseplate l0 while the apparatus is in operation but may be removed while the roll of sheeting material [2 is being changed. The roll of sheeting material I2 is supported by roller l3 which is in turn supported by member l4. Roller I3 is rotated by gear IS on rotatable shaft H which extends upward through baseplate l0 through a gas-tight bearing. Rotatable shaft I1 is held rigid by hangers l5. Gear l9 at the bottom of shaft meshes with gear 2| on rotatable shaft 23. Shaft 23 runs through shaft hangers 22 attached to supporting member 20. This shaft may be moved laterally by operation of control wheel 24. Shaft 23 is rotated by means of force applied to pulley 26 through motor 25. Gear 21 on shaft 23 may be meshed with gear 28 on rotatable shaft 29 by the manipulation of wheel 24. Rotatable shaft 29 passes through a gas-tight bearing in baseplate I0 and is supported by hangers 32. Gear 3| at the top of shaft 29 turns roller 33, which is supported by member l4. Sheeting material I2 is run around roller 44 and idler roller 34. Roller 44 may be turned by gear 45 on rotatable shaft 45. Shaft 46, which is supported by hangers 41, passes through a gas-tight bearing in baseplate I0. Gear 48 on shaft 46 meshes with either gear 49 or gear 50 on rotatable shaft 23.

Evaporating boat 36 on support member 31 is adapted to be filled with the material which it is desired to vaporize. Leads 38 and 39 from induction heating coil 40 are for connection to a source of high frequency electric current whereby the material to be vaporized may be heated to the vaporization temperature.

Extending downward from baseplate I0 is gastight manifold 5| which communicates with the coating chamber through an opening in baseplate |0. Communicating with manifold 5| are four diffusion pumps 52 which in turn communicate with exhaust manifold 53. Exhaust manifold 53 is evacuated through conduit 54 by means of mechanical pump 55. Mechanical pump 55 is shown in Fig. l but not in Fig.2.

Conduit 56 is connected through valve 51 to manifold 5|. Conduit 58 is attached to conduit 56 through T-connection 59. Attached to con- 3 duit II is mechanical pump I similar to mechanical pump II. In Fig. 1 mechanical pump II is directly in back of mechanical pump II.

Conduit II forks at T-connection I i One fork passes through valve I! to degassing chamber II. The other fork passes through valve II to condenser II of ejector-condensation pump II.

Conduit I6 runs from manifold ll through valve I! to the high-vacuum connection of pump SI. It also runs through T-connection II and valve II to degasser Ii.

Pump II is of the oil diffusion type in which boiler ll heats oil until it vaporizes. These vapors pass up conduit 12 and enter pump chamber II where they pass through a nozzle and diffuser. In the course of their passage from conduit I! through pump chamber II the oil vapor molecules have entrained gases from conduit II. At the lower end of pump chamber II most of the oil molecules are condensed and return to the boiler by gravity flow through conduit II. The noncondensable gases together with a small quantity of oil vapor molecules pass upward into condenser II where the remaining oil vapor molecules are condensed and flow back by gravity through. conduit 1: to the boiler. The noncondensable gases pass through conduit 'II and are removed by the mechanical pump (not shown) connected to conduit II.

Conduit II is weldedito conduit II. Conduit II is connected to small mechanical pump 11. Small mechanical pump 11 is used as a holding pump for oil diffusion pump II during periods when it is valved out of the system.

Degassing chamber II has a cover plate I! mounted on wheels II for convenience in handling. Wheels II move on track II. Cover plate I2 is in gas-tight connection with baseplate II during operation. Baseplate I5 is held by supporting member II.

Extending perpendicularly from baseplate II is column II which rigidly supports end plate II. Extending between baseplate II and end plate I1 are rollers II and II. Rollers II are idlers while rollers II are rotated by pulleys I2 which are driven by belts II running between pulleys I! and motor II. Control panel I5 is used to reverse and vary the speed of motor II. The two shafts rotated by pulleys I2 pass through gas-tight bearings in baseplate II.

The apparatus illustrated in Figs. 1 and 2 may be operated with bo h the coating and degassing chamber working or with either chamber alone. At the same time either chamber may be brought into operation after the other is operating with minimum shut-down time of the operating chamber. By way of illustration, let it be assumed that it is desired to begin operations. Valves II, II, and II are closed and mechanical pump TI is holding oil condensation pump 64 in readiness for operation. Valve I2 is closed and valve I] opened. Mechanical pump I0 is started and the coating chamber evacuated to the proper pressure (less than 1 mm. Hg) for operation of diffusion pumps 52. Mechanical pump II and diffusion pumps I! are then started and the coating chamber is brought down to operating pressure (about -4 mm. H8 or lower). Induction heating coil 40 is energized. Motor 25 is started and the roll of degassed sheet material begins to turn, exposing the material to the molecules vaporizing from boat II. The coating chamber is now operating.

Valve I1 is closed and valve I! opened. Pump I0 now operatu to bring the pressure of the degassing chamber down to the operating pressure of the oil condensation ejector pump. At this point valve I2 is closed and valves II and II opened so that oil condensation ejector pump II is brought into the system. The pressure is then brought down to about 10 microns Hg and the degassing chamber is ready for degassing operations. Motor II is started and ,rolls of work material (not shown) are unwound from one of the rollers II around the idler rollers II and rewound on the other roller II. Exposure to the high degree of vacuum removes gases from the material and places it in proper condition for use in the coater. Motor II may-be reversed so as to provide for repeated exposure of the roll of material to the degassing action of the vacuum.

If it is desired to place the coating unit in operation after the degassing unit has been started, it is a simple matter to close valves II, II, and II and open valve Il. Oil condensation ejector pump 84 is then held in operating condition by mechanical pump II (which operates whether pump II is or is not backing up pump II) and pump II takes the coating chamber down to the pressure where difl'usion pumps II are effective whereupon pumps I2 backed by pump 55 are put into operation. This takes no more than about 5 minutes and the degassing chamber may then be quickly placed in operation again.

Valve I1 is used when it is desired to employ as a condensing surface for vapors of the substance doing the coating. Natural fibers such as cotton and silk may be used but the coating is usually not very adherent. Artificial materials such as cellulose acetate, cellulose nitrate. and glass fabrics form good bases for the coating of adherent films. Substances which may be vaporized and coated on the above-mentioned materials include nonconductors as well as conductors. Usually it is desired to coat with metals such as aluminum, nickel, beryllium, platinum, gold, silver, etc., but a nonconductor such as quartz may also be used.

While the invention has been described in considerable detail with reference to a preferred embodiment thereof, it will be understood that modifications and variations therein may be effected without departing from the spirit and scope of the invention as it is defined by theappended claims.

What we claim is:

1. Apparatus for degassing and coating material under vacuum comprising in combination a gas-tight chamber for containing material to be treated, a mechanical backing pump of substantial capacity, conduit means connecting said mechanical backing pump and said chamber, valve means in said conduit means between said mechanical backing pump and said chamber for closing said conduit means, an ejector pump having a pumping range of about 10-1000 microns Hg, secondary conduit means connecting the low pressure side of said ejector pump with said chamber and connecting the high pressure side of said ejector pump with said first-named conduit means between said valve means and said mechanical backing pump, shut-off valve means in said secondary conduit means on each side of said ejector pump for isolating said ejector pump from the remainder of said apparatus, and high vacuum pumping means connected to said chamber for evacuating said chamber in the pressure range below about microns Hg and comprising a plurality of diflusion pumps backed by a second mechanical pump of substantial capacity.

2. Apparatus for degassing and coating material under vacuum comprising in combination a gas-tight coating chamber and a separate gastight degassing chamber, conduit means extending between said chambers in communication with each said chamber, a mechanical backing pump of substantial capacity communicating with said conduit means, spaced-apart valve means in said conduit means for closing said conduit means between said mechanical backing pump and each said chamber, an ejector pump having a pumping range of about 10-1000 microns Hg, secondary conduit means connecting the low pressure side of said ejector pump with said degassing chamber and connecting the high pressure side of said ejector pump with said firstnamed conduit means at a point between said spaced-apart valve means, shut-ofi valve means in said secondary conduit means on each side of said ejector pump for isolating said ejector pump from the remainder of the system, and pumping means connected to said coating chamber for evacuating said coating chamber in the pressure range below about 10 microns Hg.

3. Apparatus for degassing and coating material in strip form under vacuum comprising in combination a gas-tight coating chamber, means for vaporizing coating material within said chamber, controllable means for rolling and unrolling material to be coated within said chamber in proximity to said vaporizing means, a separate gas-tight degassing chamber for degassing material to be coated, controllable means for rolling and unrolling material to be degassed within said chamber, conduit means connecting said champressure conduit means connecting the low pressure side of said ejector pump with said coating chamber and said degassing chamber respectively, shut-off valve means in said low pressure and high pressure conduit means respectively for isolating said ejector pump, and high vacuum pumping means connected to said coating chamber for evacuating said coating chamber in the pressure range below about 10 microns.

4. Apparatus for degassing and coating material in strip form under vacuum comprising in combination a gas-tight coating chamber, means for vaporizing coating material within said chamber, controllable means for rolling and unrolling material to be coated within said chamber in proximity to said vaporizing means, a separate gas-tight degassingchamber, controllable means for rolling and unrolling material to be degassed within said chamber, conduit means connecting said chambers, spaced-apart valve means in said conduit means, a mechanical backing pump of substantial capacity connected to said conduit means between said spaced-apart valve means, an ejector pump having a pumping range of about 10-1000 microns Hg, a small mechanical pump 7 connected and arranged to back said ejector pump, secondary conduit means connecting said ejector pump with the remainder of said apparatus, said secondary conduit means comprising a conduit connecting the high pressure side of said ejector pump with said first-named conduit means between said spaced-apart valve means and a second conduit extending from the low pressure side of said ejector pump and being branched with a conduit branch connecting said ejector pump with each of said chambers, shutoff valve means in said secondary conduit means for isolating said ejector pump and small mechanical pump from the remainder of the apparatus, and pumping means connected with said coating chamber for evacuating said chamber in the pressure range below about 10 microns H and comprising a plurality of difiusion pumps backed by a second mechanical backing pump of substantial capactiy.

JANIES WISHART. GEORGE HUBERT BANCROFT.

REFERENCES CITED The following references are of record in the file of this patent:

, UNITED STATES PATENTS Number Name Date 2,241,228 Weinhart May 6, 1941 2,384,500 Stoll Sept. 11, 1945 2,402,269 Alexander et a1. June 18, 1946 Patent No. 2,557,584

Certificate of Correction A June 19, 1951 JAMES WISHART ET AL. It is hereby certified that the name of co-inventor in the above numbered patent was erroneously described and specified as George Hubert Bancroft whereas said name should have been described and specified as George Herbert Bancroft; in the printed s ification, column 4, line 35, for valve 51 read valve 67; and that the sai Letters Patent should be read as corrected above, ,0 that the some may conform to the record of the case in the Patent Ofice.

Signed and sealed this 25th day of September, A. D. 1951.

THOMAS F. MURPHY,

Assistant Commissioner of PM. 

